一株内生砖红镰刀菌促进烟草生长和增强青枯病抗性

A strain of endophytic Fusarium lateritium promotes growth and resistance to bacterial wilt of tobacco

课题组前期报道了一株对马铃薯具有促生防病作用的内生砖红镰刀菌Fusarium lateritium(FL617)。为拓展该菌株的应用范围,本研究以同为茄科作物的烟草为研究对象,探究了砖红镰刀菌对其生长和抗病的影响。结果表明,与对照组相比,处理组叶表面积、主根数、叶片数、叶绿素a和叶绿素b含量分别提高了5.0、3.9、1.4、1.3和1.3倍;该结果表明砖红镰刀菌对烟草具有促生作用。生测结果表明,砖红镰刀菌增强了烟草对青枯病的抗病性,其青枯病病情指数下降约30%。植物激素合成相关基因表达模式分析,发现处理组植物激素合成相关基因表达显著上调(1.6–39.9倍);用青枯病菌Ralstonia solanacearum感染寄主植物后分析其水杨酸(SA)、茉莉酸(JA)和R基因信号相关基因的转录模式,发现与对照组相比,处理组SA、JA相关基因均显著上调(1.2–8.3倍),仅有一个R基因显著下调(50%)。进一步用GFP标记的菌株进行荧光定殖观察,发现植物根系周围簇生着带有绿色荧光信号的真菌菌丝,表明砖红镰刀菌可以定殖于烟草根系。综上所述,推测砖红镰刀菌F.lateritium能够通过定殖于烟草根系介导植物激素、免疫防御相关基因的表达从而影响植株的生长发育和抗病性。

Our research team previouly reported an endophytic Fusarium lateritium strain that could promote growth and disease resistance of potato.In this study,tobacco,another Solanaceae crop,was used as the target to explored the influence of F.lateritium on growth and disease resistance of tobacco.The results showed that in comparison with the control,the leaf surface area,the number of main roots,the number of leaves and the content of chlorophyll a and b of the treated plants increased by 5.0,3.9,1.4,1.3 and 1.3 folds,respectively,demonstrating that F.lateritium could promote the growth of tobacco.In addition,F.lateritium enhanced the resistance of tobacco to bacterial wilt,and the bacterial wilt disease index decreased by about 30%.It was found that the expression of phytohormone synthesis related genes in the treated plants was significantly up-regulated(1.6–39.9 folds).After infection with the pathogen of tobacco bacterial wilt,Ralstonia solanacearum,the transcription patterns of the related genes of salicylic acid(SA),jasmonic acid(JA)and R gene signal were analyzed.It was found that the SA and JA related genes were significantly up-regulated in the treated tobacco plants(1.2–8.3folds)while only one R gene was significantly down-regulated(50%).Observation of fluorescence colonization of GFP-labeled strain showed clusters of fungal hyphae with green fluorescence signals surrounded the plant roots,indicating that F.lateritium could colonize the tobacco roots.It is inferred that F.lateritium can mediate the expression of plant hormones and immune defense related genes via colonization in tobacco roots,thereby affecting growth and disease resistance of the host plant.